Polylactide (or poly lactic acid) resins are a kind of resin containing a repeating unit of the following Formula 1. Unlike the existing petroleum-based products, these polylactide resins are based on biomass, and thus they have environment-friendly features such that they can be used as a renewable resource, and showing low carbon dioxide emissions that contribute to global warming during their production, compared to other resins, and being biodegradable in the presence of moisture and microorganisms, as well as having suitable mechanical strength equivalent to the existing known petroleum-based products.

These polylactide resins have been mainly used for disposable packaging/containers, coatings, foam products, films/sheets, and fabric. Recently, there have been many trials of use of the polylactide resins as semi-permanent materials for mobile phone bodies or car interior parts, after their physical properties are improved by mixing the polylactide resins with known resins such as ABS, polycarbonate, and polypropylene. However, their application is still limited because the polylactide resins have a weak physical property of biodegradation by factors such as catalysts used in their production or moisture in air.
Further, although the polylactide resins have an advantage of showing relatively high mechanical strength, they are problematic in that they have a relatively high glass transition temperature of room temperature or higher (Tg, 50˜60° C.) and thus become brittle when applied to film or sheet products because of reduced resin flexibility after thermal processing. Furthermore, due to their low impact resistance, their application is still limited. Until now, in order to improve elasticity, there have been many trials in which the resins are compounded with organic materials such as rubber or branches are introduced into the main chain of polylactide, but the effects are still unsatisfactory.